A mixing valve for mixing hot and cold water can deliver a tempered water mixture to a flexible-pipe spray head or sprinkler for a rinsing table or the like and comprises a valve housing connectable to hot and cold water supply pipes having a mixing or outlet chamber which is connected with a water outlet piece which is a withdrawable sprinkler hose with a sprinkler head or spray head from which the water is discharged.
A mixing fixture of this type is known to us to have been in use. It has the disadvantage that when the supply of water is interrupted, the pressure in the supply pipes drops and a reverse flow by suction can develop. If during the reverse-flow period the sprinkler hose outlet is put down in the basin, dirty water can be drawn through the hose by the vacuum or suction and can reach the water supply pipes.
This is unhygienic. Of course it is already known to connect a vent valve in the vicinity of a water outlet in certain water fixtures. Arrangements of this latter type are however not significant for a faucet with a withdrawable sprinkler hose outlet.